ana.chem exam 2

Symbol for population mean

μ

Symbol for sample mean

x

Symbol for population variation

σ²

Symbol for sample variance

s²

Symbol for population standard deviation

σ

Symbol for sample standard deviation

s

What does RSD stand for

Relative Standard Deviation

What is the symbol for degrees of freedom

v

What is degrees of freedom

the number of data points that can be INDEPENDENTLY specified.

True or False: We always know the true value.

False

True value is ____ to be known

assumed

Who was the founder of small sample statistics

William Gosset

What was William Gosset’s Alias name

Student

Which Test did William Gosset invent? T, F, or Q test?

T test

What was the name of the Brewery William Gosset worked for?

Guinness Brewery

What is confidence interval?

Range of values that include the true value 

What are the two extreme values called?

Confidence limits

What is the purpose of F-test?

Compare precisions

What is the purpose of T-test

Compare means

What is the purpose of Q-test

Detect Outliers

What is the purpose of Grubbs test

Detect Outliers

If the calculated value is smaller, the null hypothesis is…

accepted

If the calculated value is larger, the null hypothesis is…

rejected

F-test allows to conclude whether the variances of 2 sets are…

significantly different from each other

What is the parameter (statistic) to be calculated in an F-test is…

F

Who is the F-test named after

Sir Ronald A. Fisher

When is the two-tailed test used?

When asked if the values differ significantly (no direction)

When is a one-tailed test use?

When asked if the value is GREATER or SMALLER than the other (direction)

What is a T-test used for:

Compare mean and true value. or to compare 2 means. 

Route 1 of T-test:

1. Conduct an F-test

2. If variances do not differ, calculate S pooled

3. Find t-cal and compare with t-critical value.

(v/ DOF= n1+n2-2)

Route 2 for T-test

1. Do F-test

2. If variances differ, use Welchs t-test

3. Find t-crit and compare it to t-cal

What is a Q-test used for

To decide if an outlier should be retained or thrown away

For a Q-test, if value is accepted, value should be…

Retained

For a Q-test, if value is rejected, value should be…

Thrown away

Which test is the max normalized deviation test

Grubb’s Test

Scientific notation

A way of expressing a number in its general form

Scientific form (N = a x 10^b): What does N, A, and B stand for?

N is the number, A is the coefficient, and b is the integer.

What is this an example of and what does each number stand for?

31.4 = 3.14 ×10^1

Scientific notation. N = 31.4, A = 3.14, b = 1.

(move decimal point as directed by integer exponent)

(left is positive, right is negative)

What are significant figures?

minimum number of digits needed for a given value in scientific notation without the loss of precision

When is a zero considered a significant number?

1. in the middle of a number

2. At the end of the number on the RIGHT side of the decimal

How many significant figures are needed for a correct answer?

4 significant figures (round off the result to four digits)

What is a mantissa

The decimal part of the logarithm

True or False: The mantissa will contain the same number of digits as the number of significant figures in N

True

True or False: The anti-log will have the same number of significant figures as the number of digits in the N.

False, Same as the number of significant figures in the mantissa.

What is an equilibrium

Condition of balance between 2 opposing tendencies

What is the difference between forward and reverse reaction?

The forward reaction goes (points) to the products.

The reverse reaction goes to the reactants (backwards)

What does the dynamic nature of equilibrium state?

Rate of Forward Reaction = Rate of Reverse Reaction

• The changes caused by the forward reaction is exactly counterbalanced by the changes caused by the reverse reaction

• Continuously go on

• No macroscopic changes

Who discovered reversibility of chemical reactions in 1803

Claude Berthollet

Who discovered Law of Mass Action in 1867

Cato Guldberg and Peter Waage

What letter represents equilibrium constant

K

Equilibrium constant is…

Dimensionless

Who stated: “if a system in equilibrium is disturbed by an external force, the system proceeds to a NEW EQUILIBRIUM such that the disturbance is partially offset”

Henri Louis Le Chatelier

What is the difference between K and Q

Q does not have to be in the equilibrium for it to be calculated. (it can be calculated at both equilibrium and non-equilibrium)

Fill in the blanks:

If Q=K, the system is _____

If Q<K, the reaction must proceed ______

If Q>K, the reaction must proceed _____

at equilibrium

right to reach equilibrium

left to reach equilibrium